The primary purpose is to determine the tolerability of administering oral doses of tirapazamine at the highest suggested dose level. Secondary, to assess pharmacokinetic profile, to assess cumulative tolerability, and to assess the absolute bioavilability of an oral preparation at different dose. There were 36 patients that participated on the seven escalating-dose levels. Four on dose group 1, three on dose group 2 three on dose group 3, three on dose group 4 seven on dose group 5, seven on dose group 6, and nine on dose group 7.